Balance-wheel bridge for watches.



PATENTED MAR. 5, 1907.

E. H. HORN. BALANCE WHEEL BRIDGE FOR WATCHES.

APPLICATION FILED 0613.29, 1906.

summon n c UNITED STATES PATENT OFFICE.

ERNEST H. HORN, OF WATERBURY, CONNECTICUT, ASSIGNOR TO THE WA- TERBURY CLOCK CO., OF WATERBURY, CONN ECTICUT, A CORPORATION.

BALANCE-WHEEL BRIDGE FOR WATCHES.

Specification of Letters Patent.

Patented March 5, 1907.

Application filed October 29,1906. erial No. 341,088.

To (ti/Z whont it may concern:

Be it known that I, ERNEST H. HORN, a citizen of the United States, residing at Vaterbury, in the county of New Haven and 5 State of Connecticut, have invented a new and useful Improvement in Balance-\Vheel Bridges for -Watches; and I do hereby declare the following, when taken in connection with the accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and represent, in

Figure 1 an enlarged broken plan view of a watch provided with my improved balancewheel bridge; Fig. 2, a detached plan view of the bridge; Fig. 3, a view thereof in side elevation; Fig. 4, a view of the bridge in transverse section on the line a b of Fig. 2; Fig. 5, a sectional view through the spring-receiving finger of the bridge on the line (Z of Fig. 3, this view being on a larger scale and showing the outer end of the spring in full lines and the body of the bridge in broken lines; Fig. 6, a corresponding sectional view of the spring-receiving finger on a still larger scale.

My invention relates to an improvement in balance-wheel bridges for watches, the object being to produce a simple, effective, and convenient bridge constructed with particu lar reference to cheapness, uniformity, and accuracy of manufacture and to reducing to the minimum the task of timing the watch.

I/Vith these ends in view my invention consists in a sheet-metal balance-wheel bridge having certain details of construction, as will be hereinafter described, and pointed out in the claim.

In carrying out my invention, as herein shown, I form a fiat integral spring-receiv ing finger 2 upon the edge of a sheet-metal bridge 3 and locate the finger flatwise in a plane passing through the center of the pivotbearing, which is not shown, but which is located in the circular opening 4. This plane is represented by the broken line 5, Figs. 5 and 6, and the center of the pivot-bearing is designated by 6 in the same figures. The finger is formed with a centrally-located transverse hole 7 for the reception of the outer end of the balance or hair spring 8 and l of the pin 9, by means of which the end of the spring is secured in place. The spring being of the usual form only the outer end of it is shown. By locating the finger 2 in a plane intersecting the center of the pivotbearing the plane of the finger is located at a right angle or at approximately a right angle to the outer end of the spring. From this it follows that the hole 7 in the finger will be in line or approximately in line with the outer end of the spring. It is true that the outer end of the spring partakes of the curvature of the entire spring, but the hole being large with respect to the size of the spring the same accommodates itself in the hole with the minimum of displacement. In other words, the outer end of the spring does not have to be displaced or pulled around in order to enter it into the hole in the finger.

As shown in Fig. 6, and preferably, the outer end of the spring is formed with a shoulder 10, which is brought to a bearing upon the finger and positions the spring, so that if the spring is carefully regulated with respect to the balance-wheel before the balance-wheel and spring are applied to the bridge the spring will not require further adjustment beyond those very fine adjustments secured by the regulator-lever that is to say, it will not be necessary to draw the outer end of the spring one way or the other through the hole 7 in the finger 2 in order to adjust the spring to the point where the more delicate adjustments of the regulatorlever can step in and effect a final adjustment.

I am ware that sheet-metal bridges for watch-movements have been provided with sheet-metal studs formed with a hole for the reception of the outer end of the hair-spring and a pin for securing the same in place. This construction requires the perforation of the bridge for the reception of the shank of the stud and the swaging of the stud in place. These operations being minute in scale are laborious, expensive, and productive of fac tors of error dilficult to correct, as the riveting of the studs in place causes them to be deflected enough to demand fine adjustments and, moreover, they are apt to get loose, nor has it ever been proposed to locate these studs in the plane of the center of the pivot- I spring and the pin by which the said end is bearing of the bridge. I secured in place.

I claim In testimony whereof I have signed this A sheet-metal balance-wheel bridge for l specification in the presence of two subscrib- 5 watches, provided with a flat integral springing witnesses.

receiving finger arranged to stand l'latwise in T a plane passing through the center or ap- ERNESI HORD" proximately the center of the pivot-bearing l itnesses:

of the bridge, and formed with a hole to re- CLEMENT I. GRIGGS, I0 ceive the outer end of the balance or hair CLARENCE W. SHADER. 

